Gheorghiu has concentrated her repertoire on several different roles: Violetta, Mimì, Magda, Adina, and Juliette. In 2003, she debuted as Nedda in Pagliacci and as Marguerite in Faust. A soprano with a large range and a dark coloured voice,[6] Gheorghiu is also able to sing spinto roles. She has recorded Tosca (also made into a film in 2001, directed by the French director Benoît Jacquot) and Leonora in Il trovatore for EMI and sang in her first Tosca at the Royal Opera House, Covent Garden, in 2006. Her performance was an overall success, although because the famous Zeffirelli production of 1964 was replaced by a new production (which premiered with her), there was comparison between the Toscas of Gheorghiu and Maria Callas, for whom the Zeffirelli production was designed.

Gheorghiu took part in many concerts, singing alone or together with her colleagues. Among the most important ones, the reopening of the Royal Opera House Covent Garden (1999) and Teatro Malibran in Venice (2001) and at the opening the new Opera House in Valencia, in the presence of the Queen Sofia of Spain (2005). She sang at the "Prom at the Palace" (2002), the event that marked the Jubilee of Queen Elizabeth II, a concert that is available on DVD. She also sung at the Queen Beatrix's Jubilee Gala in Amsterdam (2005), at the New Year's Eve Concert at Palais Garnier in Paris (2006), at the "Met Summer Concert" in Prospect Park, New York (2008) or at the Memorial Concert for Luciano Pavarotti in Petra (2008). In 2009, Gheorghiu was invited to honor Grace Bumbry during the 32nd Annual Kennedy Center Honors, in Washington, DC. She performed "Vissi d'arte" from Puccini's Tosca in the presence of Barack Obama, the president of the United States.[7]

In December 2000, Gheorghiu performed the title role in the film Tosca, directed by Benoit Jacquot, together with Roberto Alagna and Ruggero Raimondi.[8] One year later, in 2002, Gheorghiu interpreted Juliette in the movie Roméo et Juliette, alongside Roberto Alagna and Tito Beltrán, also released on DVD.[9]

In November 2010, Gheorghiu made her debut in Cilea's Adriana Lecouvreur, a new production of the Royal Opera House, Covent Garden. The Observer wrote, "It's hard to imagine anyone bettering Angela Gheorghiu in this part. Her voice, feather-light and creamy yet with a core of steel, matches the liquid way she moves on stage. She's a natural actress and made the improbable death scene heartbreakingly believable and her signature aria 'Poveri fiori' simply unforgettable."[10]The Telegraph wrote, "Adriana is known as a nice, easy sing for ageing or challenged prima donnas (no difficult top notes, and a tame orchestra), so Gheorghiu, in her vocal prime, should have found it a doddle. But her first aria was bumpy and nervous, and she fudged the end of the second. Elsewhere, in duet and declamation, she often sang exquisitely."[11]

In July 2011, Gheorghiu sang the title role in Tosca at the Royal Opera House conducted by Antonio Pappano, and the following September returned there for the revival of Faust, which was broadcast live in cinemas all over the world. In April 2012, she appeared for the first time at the Teatro Colón, Buenos Aires, in a concert of duets with Roberto Alagna.[12]

In June 2012, Gheorghiu celebrated 20 years since her debut on the stage of the Royal Opera House, London, by performing in La bohème with Roberto Alagna. In July 2012, she held her first master class at the Georg Solti Accademia in Castiglione della Pescaia, Italy. In November 2012 she returned to San Francisco Opera to perform in Puccini's Tosca. In an interview[13] to Kurier from February 2014, Gheorghiu expressed interest in performing the role of Norma and in recording the role of Desdemona (Otello). Her most recent role debut was as Charlotte in Massenet's Werther in March 2015 at the Vienna State Opera, to great critical acclaim.[14]

She has recorded many recital albums and complete opera recordings and often appears on television and in concerts. Although Gheorghiu has not won an individual Grammy award, the EMI recording of Massenet's Manon with Gheorghiu in the title role won the 2001 Gramophone Award for "Best Opera Recording", was nominated for "Best Opera Recording" in the 2002 Grammy Awards.[15][16] The EMI recording of Puccini's Tosca with Gheorghiu, Roberto Alagna and Ruggero Raimondi in the title roles brought her the Deutscher Schallplattenpreis award in 2002.[17] She also won Diapason d'Or Awards, Choc du Monde de la Musique in France, Cecilia Prize in Belgium, the Echo Award, the Italian Musica e dischi, Foreign Lyric Production Award, the USA Critics' Award. Gheorghiu won the title of Female Artist of the Year at the Classic Brit Awards in 2001 and 2010.[18] She was honoured with "La Medaille Vermeille de la Ville de Paris" and she was appointed an Officier de l'Ordre des Arts et des Lettres and Chevalier de l'Ordre des Arts et Lettres by the French Ministry of Culture and by her native country Romania.[citation needed] In December 2010, Gheorghiu was awarded a Doctor Honoris Causa by the University of Arts in Iasi (Romania)[19] and the Star of Romania, the highest decoration given by the President of Romania.[20] In October 2012, Gheorghiu received the Nihil Sine Deo royal decoration from His Majesty King Michael I, honoring her contribution to promoting Romanian culture in the world.[21]

On occasion, Gheorghiu has had difficult relationships with opera house managements and directors. Some, but not all, of them have stemmed from her opposition to directors who, as she put it in an interview with ABC "want to express their own fantasies, forgetting about the characters. At times, she says, what they put on stage goes against both the story and the music."[22] She has attributed her outspokenness to her upbringing in Romania under the totalitarian regime of Nicolae Ceaușescu:

Because I grew up in a country where there was no possibility of having an opinion, it makes me stronger now. Lots of singers are frightened about not getting invited back to an opera house if they speak out. But I have the courage to be, in a way, revolutionary. I want to fight for opera, for it to be taken seriously. Pop music is for the body, but opera is for the soul.[23]

Gheorghiu had a problematic relationship with former Metropolitan Opera General Manager Joseph Volpe after her debut there as Mimì in 1993. In 1996, Gheorghiu was cast as Micaela in a new production of Carmen, opposite Waltraud Meier and Plácido Domingo. The production by Franco Zeffirelli called for Micaela to wear a blonde wig, which Gheorghiu disliked. When the Met toured the production in Japan in 1997, she refused to wear it on the first night to which Volpe famously declared, "The wig is going on, with you or without you" and replaced her with an understudy.[24][25] She appeared at the Met again in 1998 for six performances of Roméo et Juliette with her husband, tenor Roberto Alagna as Roméo. Volpe had planned to engage Gheorghiu in Violetta Valery for a new production of La traviata, to premiere in November 1998 and directed by Zeffirelli. Alagna was to sing the role of Violetta's lover, Alfredo Germont. According to Volpe, Gheorghiu and Alagna argued with the staff and the director over production details and continually delayed signing the contract. They eventually signed their contracts, and faxed them to the Met one day past their deadline. Volpe refused to accept them. The production opened with Patricia Racette and Marcelo Álvarez as the lovers.[24]

In September 2007, Gheorghiu was dismissed from Lyric Opera of Chicago's production of La bohème by General Manager William Mason, for missing rehearsals and costume fittings, and generally "unprofessional" behavior. Gheorghiu said in a statement that she had missed some rehearsals to spend time with her husband, who was singing at the Met in Roméo et Juliette and rehearsing for Puccini's Madama Butterfly and added, "I have sung 'Boheme' hundreds of times, and thought missing a few rehearsals wouldn't be a tragedy. It was impossible to do the costume fitting at the same time I was in New York.[26]

Six weeks later, Gheorghiu made her debut at San Francisco Opera receiving favorable reviews for her Magda in that company's new production of La rondine.[27][28] The San Francisco Opera production originated with London's Royal Opera House, where it premiered on May 7, 2002 with Gheorghiu and Alagna as Magda and her lover Ruggero. It is one which she particularly admires: "When the curtain opened on La rondine at Covent Garden, the audience gasped and applauded. People want to dream. If directors want to do something new with operas, why not do something beautiful?[29]

Despite these issues, Gheorghiu and Alagna returned to the Metropolitan Opera for five performances of L'elisir d'amore in 1999 and for four performances of Faust in 2003. Gheorghiu also performed at the Met as Liù in Turandot in 2000; as Violetta in La traviata opposite Jonas Kaufmann in 2006 and 2007; as Amelia in Simon Boccanegra in 2007; as Mimì in La bohème in 2008; as Magda in the 2008/09 season in the ROH/SFO production of La rondine, the Met's first performance of the opera since 1936; and for the 2009/10 season she appeared as Violetta, replacing her previous engagement as Marie Antoinette in a rare revival of John Corigliano's The Ghosts of Versailles which was replaced due to the recession.

On December 31, 2008, Gheorghiu premiered the new production of La rondine at the Met, together with Roberto Alagna, Marius Brenciu, Lisette Oropesa and Samuel Ramey. The opera was last performed at the house over 70 years ago. She received some favorable reviews for her Magda: "Gheorghiu embodies the part, as actress and singer, with her natural charisma."[30] The New York Times opinion was more mixed: "Vocally, both leads are somewhat disappointing. Ms. Gheorghiu, as Magda, sings with gleaming sound and wonderfully dusky colorings in the strong top register of her voice. But the earthy richness of her mid-range singing sometimes turns breathy, and her low voice is curiously weak."[31]

In August 2009, Gheorghiu canceled all her scheduled 2010 Met performances of Carmen, for "personal reasons".[32] It was to have been her first public performance of the title role (written for and normally sung by a mezzo-soprano). This was later attributed to her separation from her husband, Roberto Alagna, who was scheduled to sing opposite her.[33] She also cancelled other Met performances scheduled near the end of 2010. In March 2011 she cancelled all her scheduled performances of Gounod's Roméo et Juliette at the Met, citing illness. Only days later she cancelled all her performances in the scheduled new production of Faust during the Met's 2011/2012 season. According to her manager, "She felt uncomfortable in the concept". Peter Gelb, the Met's general manager, said that her frequent cancellations had become "an increasingly difficult problem for (the Met)." Gelb went on to say that, as of then, plans were still in place for Gheorghiu's return to the Met stage. He also said, "This has nothing to do with wigs.".[34] Gheorghiu returned to the Met in December 2014 to perform to great critical acclaim [35] as Mimi in La Bohème, opposite Michael Fabiano. For the 2015-2016 season, she is scheduled to perform her first MET Tosca, in the Bondi production[36].

Divorced from her first husband, from whom she retained her surname, Gheorghiu married tenor Roberto Alagna in 1996. The couple have sung together often on stage and on studio recordings. She was once chosen the 74th "sexiest woman in the world" by the magazine FHM.[37] In October 2009, Alagna said in an interview in Le Figaro that he and Gheorghiu had separated.[38]

Following the separation, she declined to appear opposite Alagna in Carmen at the Metropolitan Opera in December 2009.[39] The divorce, however, was called off in December 2009.[40] In a March 2011 interview with the Daily Express she stated that she and Alagna were back together, and they were seen together in March 2011 backstage at London's Royal Opera House where Alagna was performing in Aida. She also stated in the interview that although she still wanted to sing separately from her husband for a while, she was looking forward to the day when they could retire together and have their own pets.[41][42][43] Later that year, they jointly opened a Greek amphitheatre in the Emirate of Qatar.[44] In June 2012, they sang together in two performances of La bohème at The Royal Opera House to commemorate the 20 years since they had met in the very same production. They also sang at a joint concert in Buenos Aires, and planned to perform together in Manon Lescaut and Adriana Lecouvreur in future seasons.[45] Gheorghiu said of their separation, "It was stupid of us to be apart."[46] However, in January 2013, she announced that they had agreed to divorce.[47]